Update internal/global/trace testing

[MrAlias]

Use existing testing types instead of the oteltest package.

Part of #2077

[codecov]

Codecov Report

Merging #2111 (14b6fc7) into main (7f10ef7) will decrease coverage by 0.1%.
The diff coverage is n/a.

@@           Coverage Diff           @@
##            main   #2111     +/-   ##
=======================================
- Coverage   73.1%   72.9%   -0.2%     
=======================================
  Files        167     167             
  Lines       8237    8237             
=======================================
- Hits        6027    6011     -16     
- Misses      1977    1992     +15     
- Partials     233     234      +1     

Impacted Files	Coverage Δ
oteltest/config.go	72.9% <0.0%> (-21.7%)	⬇️
trace/config.go	61.2% <0.0%> (-14.3%)	⬇️
oteltest/span.go	97.1% <0.0%> (-2.9%)	⬇️
trace/noop.go	56.2% <0.0%> (+6.2%)	⬆️